Method of building log rafts



y 7, 1 947. .1. G. GIBSON 2,421,145 7 METHOD OF BUILDING LOG RAFTS FiledFeb. 28, 1945 l/VVEN 701a JAMES 'okoo/v 'leso/v under the finished raft.

Patented May 27, 1947 METHOD OF BUILDING LOG RAFTS James Gordon Gibson,Vancouver, British Columbia, Canada Application February 28, 1945,Serial No. 580,156

2 Claims.

My invention relates to improvements in log rafts and rafting methods.The objects of the invention are to provide a method of building lografts which is particularly adapted for use in rafting such heavy logsas are regularly transported in deep sea along the coast of the PacificNorthwest. Hitherto the most successful log raft built for this work wasthe so-called Davis raft which relied on a mat fabricated by binding aplurality of logs in side by side relation to form a floor on which abundle of logs totalling some millions of feet were bound and towing theentire structure to destination.

The present raft contemplates the use of the mat as a cradle on whichthe bundle of logs constituting the raft is formed and removing saidfloor for use in constructing other rafts after the superimposed loadhas been properly tightened up and bound into a substantiallycylindrical unit.

Referring to the drawings:

Fig. 1 is a transverse view of the mat on which the raft is to beformed.

Fig. 2 is a transverse view showing the mat substantially immersed inthe water and the raft formed thereon.

Fig. 3 is an end view of the finished raft with the mat portionsremoved.

Fig. 4 is a longitudinal view, part in section, showing the preferredmethod of cinching the raft lengthwise.

In the drawings like characters of reference indicate correspondingparts in each figure. With a view to clearly showing the ropes or cablesbinding the several parts of the mat and the raft together, the logs areshown somewhat spaced apart, but it will be understood that the logs arebound together as tightly as possible to withstand the working of thestructure during towing, etc.

The numeral l indicates a mat which is formed in two sections 3 and 4.Each section is made up of logs 5 which are floated in side by siderelation as shown in Figure 1 and are connected together by a pluralityof wire ropes 5 preferably laid alternately over and under adjoininglogs, across each section 3 or 4 and. back to starting point where thefree ends of the ropes are clamped together as at l, leaving a freelength 8 of said ropes lying in the water to be later used for thepurpose of hauling the section to which it is attached from It will beunderstood that these mats and the rafts built upon them are greatly inexcess of the length of any log used and that particularly in the makingof the mat some logs may be joined together lengthwise by boom chains orother appropriate devices so that the mat when made 'up will not beliable to elongation due to some of the logs moving endwise with respectto adjacent logs, due to water movement or the action of loading theraft logs onto the mat.

When both sections 3 and d of the mat are completed, a plurality oflines [0 are attached to the innermost logs of the section d as shown inFigure l and are passed down and around the innermost boom of thesection 3, the free ends of said lines being brought to the outer edgeof the section 4 and clamped in position as at ll, so that both sectionsmay be held together during the subsequent raft building operation.

A plurality of girth lines M are spaced at suitable intervals of thelength of the completed mat and are extended transversely across the matwith their free ends 15 descending into the water.

When sufficient girth lines are so placed, rows of logs H are laidparallel to the logs of the mat over said girth lines, the logs beingpiled from the centre of the mat outwards, the end to end abutment oflogs of one row being staggered with relation to the abutment of logs inadjacent rows so as to stiffen the ultimate raft against endwiseflexure. As the logs are piled upon the mat, so will the central portionof said mat become concavely curved so that by careful placing of thelogs the superimposed logs will assume a substantially cylindrical shapeas shown in Figure 2.

' When a sufficient quantity of logs are assembled,

the free ends l5 of the girth lines M are brought over the logs and atackle l8 secured between the ends of each girth line. The girth linesare then tightened up by winches hauling in each of the tackle ropesuntil the logs encircled by each girth line are brought into compactform. When all the girth lines are drawn up as required their free endsare clamped together by any suitable clamps as at l9, see Figure 4. Theassembled and bound bundle of logs now becomes a complete raft indicatedby the numeral 20.

In towing any bundle raft by a tow line attached adjacent the forwardend there is a tendency to elongate the raft so with a view topreventing this condition and providing a continuous endwise compactingeffort on the raft while being towed, a cable 22 is tightly bound aroundthe raft adjacent its after end and is preferably clamped at the top ofthe raft as at 23, the free end of said cable is led forward and allowedto fall in between parallel logs adjacent the upper centre of the raftand is fitted with a single sheave block 24. A second cable indicated bythe numeral 26 is securely bound around the forward end of the raft andis also clamped adjacent the top of the raft as at 21, the free end ofthis cable is passed through the block 24 and preferably led in betweenthe logs and out forwardly of the raft to form a tow line 28 therefor.When the raft is completed, clamps holding the lines Hi to the outeredge of the mat section 4 are released, tugs or other suitable haulingdevices are attached to the free ends 8 of the lines 6 and the sections3 and 4 of the mat l are pulled from under the raft 20, leaving saidraft ready for towing to destination.

The clamps l9 will preferably be ofsome approved quick release typecapable of bein collectively disconnected by detonating or other means,so that when the raft is delivered, it is only necessary to open saidclampsto allow the logs to settle and disperse over the surface of thebooming ground.

The towing cables 22 and 28 and the girth lines l4 and their clamps onlyremain to be returned to the booming ground where further rafts are tobe built.

While I have described the mat as being made up of logsand ropes bindingsaid logs together, in side by side relation, it will be obvious thatsaid mat may be made of sawn timbers spaced some reasonable distanceapart and held in position by chains, cables or other means which wouldallow the mats to conform to the underside of the raft built upon it.

What I claim as my invention is:

1. The method of building a log raft which consists of superposing logsin side by side relation upon a flexible buoyant mat until the mat hasbecome substantially concave in cross section, binding the superimposedlogs together as a bundle raft and removing the mat from beneath theraft.

2. The method of building a log raft which consists of superposing logsin side by side relation upon a flexible buoyant mat until the mat hasbecome substantially concave in cross section, binding the superimposedlogs together as a bundle raft, dividing the mat longitudinally andremoving the divided portions of said mat from beneath the raft.

JAMES GORDON GIBSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 392,691 Robertson Nov. 13, 1888715,939 Ayres Dec. 16, 1902 800,263 Campbell Sept. 26, 1905 1,142,239Davis June 8, 1915 1,488,664 Clancy Apr. 1, 1924

